2D/3D data projector

ABSTRACT

The present solution relates to a 2D/3D data projector, which comprises: A data projector, the data projector comprising: at least one micro display having an image to be projected, at least one source unit comprising at least one light source chip and at least one beam forming component, each beam forming component comprising at least one diffractive element, and each source unit being designed to preserve etendue as far as possible, to minimize photon loss, to provide a desired projection shape and a uniform illumination onto the micro display, and a focusing optical unit for projecting the image of the micro display on a target.

TECHNICAL FIELD

The invention relates to devices for displaying images by projection.

BACKGROUND

The current trend of mobility drives the consumer demand towards eversmaller portable devices, such as mobile phones, portable digitalassistants, music and video players, laptop PCs, head mounted displaysetc. As the size becomes smaller and the functionality higher, there isa fundamental problem of showing large enough visual images with verysmall devices. Because the size of a fixed screen cannot grow withoutincreasing the size of the device itself, the only reasonable way toconveniently provide visual images from small devices is to project themusing a data projector. However, the current data projectors are largein size and inefficient in nature.

The commercially available data projectors use high intensity broadbandlight sources, such as incandescent bulbs or arc lamps. These lightsources have inherently low efficiency and produce heat, which consumeshigh amounts of energy and requires a cooling system. The use of LED asa light source of data projector has also been proposed. However, thesesolutions do not have well enough optical efficiency. In these systems,the light source has poor external efficiency, and in addition to that,a large part of the light is lost in collimation. Secondly, thesesolutions are still large in size and expensive with high powerconsumption, and they cannot be operated with widely used batterytechnologies.

Another issue that is of interest to large audiences in image projectionis the issue of 3-dimensional (3D) projection. The current dataprojectors are not inherently capable of showing full color 3D imagesand the special devices that are designed to do so are expensive andrare. The media industry increases the offering on 3D movies, games andother entertainment only if 3D capable devices are commonly used.

SUMMARY OF THE INVENTION

An object of the invention is to provide an improved data projector thatis small, inexpensive and has small power consumption and is capable ofprojecting both 2-dimensional (2D) and 3D images. According to an aspectof the invention, there is provided a data projector, the data projectorcomprising: at least one micro display having an image to be projected,at least one source unit comprising at least one light source chip, andat least one beam forming component, each beam forming componentcomprising at least one diffractive element, and each source unit beingdesigned to preserve etendue as far as possible, to minimize photonloss, to provide a desired projection shape and a uniform illuminationonto the micro display, and a focusing optical unit for projecting theimage of the micro display on a target.

Preferred embodiments of the invention are described in the dependentclaims.

The method and system of the invention provide several advantages. Thedata projector has good power efficiency and the image of the projectorhas even brightness. The data projector can be made small in size, lowin weight and durable. The data projector is capable of showing both 2Dand 3D images between which the user may switch freely.

LIST OF DRAWINGS

In the following, the invention will be described in greater detail withreference to the preferred embodiments and the accompanying drawings, inwhich

FIG. 1A shows the micro display illumination with a conventional opticalarrangement,

FIG. 1B shows the micro display illumination with the opticalarrangement of the present invention,

FIG. 2A shows the beam divergence with a conventional opticalarrangement,

FIG. 2B shows the beam divergence with the optical arrangement of thepresent invention,

FIG. 3A illustrates a beam forming component integrated with a lightsource,

FIG. 3B illustrates ray traces when a beam forming component is notused,

FIG. 3C illustrates a cross section of a beam forming componentintegrated with a light source,

FIG. 3D illustrates a cross section of a beam forming componentintegrated with a light source,

FIG. 3E illustrates a cross section of a beam forming componentintegrated with a light source,

FIG. 3F illustrates a cross section of a beam forming componentintegrated with a light source,

FIG. 4A presents a single color projector with a transmissive LCD microdisplay,

FIG. 4B presents a single color projector with a reflective DMD microdisplay,

FIG. 4C presents a single color projector with a reflective LCoS microdisplay,

FIG. 5 shows a 2D/3D LCD-projector, in which both the polarizationstates are utilized,

FIG. 6 shows a 2D/3D LCoS-projector, in which both the polarizationstates are utilized,

FIG. 7 shows a LCD-projector, in which both the polarization states areutilized,

FIG. 8 shows a LCoS-projector, in which both the polarization states areutilized,

FIG. 9A shows a color projector with an X-cube beam combiner,

FIG. 9B shows a color projector with a dichroic mirror beam combiner,

FIG. 10A shows a color projector with a beam guiding component and threesource units,

FIG. 10B shows a color projector with a beam guiding component and onesource unit,

FIG. 11 shows a 2D/3D color projector with X-cube beam combiner and LCDmicro displays, in which both the polarization states are utilized,

FIG. 12 shows a 2D/3D color projector with X-cube beam combiner and LCoSmicro display, in which both the polarization states are utilized,

FIG. 13 shows a color projector with X-cube beam combiner and LCD microdisplays, in which both the polarization states are utilized,

FIG. 14A shows a color projector with X-cube beam combiner and LCoSmicro display, in which both the polarization states are utilized,

FIG. 14B shows a 2D/3D color projector with X-cube beam combiner andLCoS micro display, in which both the polarization states are utilized,

FIG. 14C shows a 2D/3D color projector with X-cube beam combiner andLCoS micro display, in which both the polarization states are utilized,

FIG. 15 shows a color projector with one source unit and LCoSmicrodisplay, in which both the polarization states are utilized,

FIG. 16 shows a color projector with dichroic mirror beam combiner andLCoS micro display, in which both the polarization states are utilized,

FIG. 17 presents an embodiment of the color projector where serialillumination is used,

FIG. 18 shows a 3D color projector, in which both the polarizationstates are utilized so that both states have separate images that areviewed through eyeglasses that have perpendicular polarization filtersfor each eye.

DETAILED DESCRIPTION OF EMBODIMENTS

The efficiency of the projector is degraded by the losses which include:spectral losses (if wideband sources are used), losses due to poorinternal efficiency of the source, losses due to poor externalefficiency of the source (for example with LEDs), light collectionlosses (collimation losses), integration losses (if several light beamsare combined), color separation losses (losses in dichroic mirrors usedto split the light into red, green and blue components), polarizationlosses (if LC-micro display is used), reflection or transmission lossesat the micro display itself for example due to a poor fill factor (gapsbetween the pixels), color combination losses (for example when usingX-cube or dichroic mirrors), and losses in the projection lens(reflection losses on the lens surfaces).

It is extremely important that the light loss is minimized in everyaspect. It is also desirable to be able to maximize the internal andexternal quantum efficiencies of the light source. The light should onlybe directed to the active area of the micro display which functions as aspatial modulator. The loss in the optical components and in the microdisplay should be minimized.

Spectral losses occur when incandescent bulbs or arc lamps are used as alight source. They emit light with a very broad wavelength band and mostof the electric power is converted to heat. By using LED (Light EmittingDiode) sources, for example, this problem can be avoided because is itpossible to create light only for the needed wavelength bands (red,green and blue).

The total efficiency of LEDs depends on the internal quantum efficiency,and the external efficiency. The definition of internal quantumefficiency is the ratio of the number of electrons flowing in theexternal circuit to the number of photons produced within the device.The external quantum efficiency means the ratio of the number of photonsemitted from the LED to the number of internally generated photons. Theinternal quantum efficiencies can be near 100%, for example 99%, withcertain materials, wavelengths and structure of the LED chip. However, alarge fraction of the generated light is never emitted from thesemiconductor, but is absorbed into the LED chip itself. This happensbecause of the big refractive index difference between the LED chip andthe surrounding material, which causes that the most of the light istrapped inside the chip by total internal reflection. The externalefficiency ratio can be as poor as 1/(4n²)≈1/50, (where n=3.5 is therefractive index of the semiconductor) for the conventional LEDs. Moresophisticated LED designs include features that allow a greater fractionof the internal light to escape. These features include hemispherical orconical semiconductor domes over the LED, surface roughening,transparent substrates and superstrates and photon recycling.Resonant-cavity LEDs use quantum electro dynamical enhancement ofspontaneous emission in high-finesse resonators. These methods allow upto 30% external efficiencies, which is still far below the optimum case.Still another proposed method is to cut the semiconductor chip into atruncated inverted pyramid by which 55% external efficiencies have beenachieved.

Light collection loss presents, along with the poor external efficiency,one of the most severe light losses in the projector system. Most of thelight coming from an LED can be collimated by using a convex lenses orreflectors based on total internal reflection or metallized reflectors.Typically this forms a relatively compact beam which has circularsymmetry. However, the circular beam is not ideal because the microdisplay can have a rectangular shape. Because of this shape difference abig portion of the light is lost. These solutions also suffer fromvignetting, i.e. the intensity of light is not even across the microdisplay. In addition to that, by using existing light collecting andcollimation techniques, the collimation of the beam can not be optimizedfor the whole optical system.

Integration losses, color separation losses and color combination lossesare difficult to improve in practice. They can be minimized by choosingdichroic mirrors, X-cubes and beam splitters carefully. When using a LCDor LCoS micro displays, the polarization losses are significantresulting in a loss of over 50%. Typically nothing is done to avoidthese losses. The micro displays have internal losses which depend onthe micro display type, modulation rate, and reflections and scatteringat the micro display itself, for example, due to poor fill factor (gapsbetween the pixels). When using an LCD micro display, the loss due topoor fill factor is typically between 20%–40%. The losses due to a poorfill factor can be decreased by applying so called micro-lens arrays(MLA) before and optionally also after the liquid crystal panel whichguides the light through the active pixel area. LCoS and DMD microdisplays have substantially better fill factors than LCD micro displays.

The losses in the projection lens can be minimized by usingantireflection coated lenses. This is a question of costs, whether tostand this loss or to use the more expensive lenses.

Source Chips:

A data projector of the invention may comprise one or more narrow bandsource chips, which work in the visible range. The source chips cancomprise of LED, OLED or quantum-well LED chips, for example, or otheralike. The bandwidth of each narrow band source chip is narrow incomparison to the whole visible range (400 nm . . . 750 nm), for examplethe bandwidth can vary from a nanometre to more than 150 nanometres,particularly the bandwidth can be from 10 nm to 50 nm. The dataprojector can be provided with one or more source chips which all emitlight with the same wavelength band. In color projectors the sourcechips provide light with different bands. Typically the source chips maytogether provide light with red, green and blue.

Source Unit:

The projector of the invention comprises one or more source units. Thesource unit comprises one or more source chips which are integrated withan innovative beam forming component. The function of the beam formingcomponent is to raise the external efficiency of the source chips, andto provide the out coupled beam with a particularly designed intensitydistribution and divergence angles.

The beam forming component provides uniform illumination to the microdisplay.

FIG. 1A shows an illuminating beam 106 on the micro display 104 when alight source 102, such as LED, is used with conventional opticalarrangements (not shown in FIG. 1). As it is seen, a substantial part ofthe light 106 does not hit the micro display 104. In addition, theillumination is not uniform and suffers from vignetting (shown usingdifferent hatchings).

FIG. 1B in its part shows an illuminating beam 110 on the micro display104 when the source unit 108 of the present invention is used. The shapeof the beam 110 is nearly rectangular so that it suitably fills themicro display 104. In addition to that, the micro display is illuminateduniformly so that vignetting is minimized.

For considerations of light loss in an optical system, the mostimportant parameter is the etendue. For a surface of arbitrary shape,the etendue in its general form is defined as (light coming frommaterial with a refractive index n₁)

${E = {\frac{n_{1}^{2}}{n_{2}^{2}}{\int{\int{{\mathbb{d}A}\;{{\hat{e}}_{A} \cdot {\mathbb{d}\Omega}}\;{\hat{e}}_{\Omega}}}}}},$where n₁ and n₂ are the refractive indices of the materials, dA is thedifferential area element on the surface, ê_(A) is the surface normalvector corresponding to dA, dΩ is the differential solid angle element,and ê_(Ω) is the centroid direction vector corresponding to dΩ.

Conservation of etendue through the whole optical system means that theoptical system is lossless. Moreover, the etendue cannot be decreased byany optical configuration. Therefore, it is crucial to design theoptical system so that the etendue is increased in a particularcomponent as little as possible.

The total flux passing through a surface can be calculated as follows:

${\phi = {\frac{n_{1}^{2}}{n_{2}^{2}}{\int{\int{{L\left( {\hat{r},{\hat{e}}_{\Omega}} \right)}{\mathbb{d}A}\;{{\hat{e}}_{A} \cdot {\mathbb{d}\Omega}}\;{\hat{e}}_{\Omega}}}}}},$where L({circumflex over (r)},ê_(Ω)) is the luminance of the surface inposition {circumflex over (r)}, to direction ê_(Ω)

In the small portable projector applications the smallest micro displayshas to be used in order to get the projector small enough. Thisconstraint typically leads to micro displays whose diagonals range from0.5 cm to 1.5 cm. The etendue of these small micro displays arerelatively near to the original etendue of the LED chip itself. Thecommercially available light collection and collimation structures forLED chips do not preserve the etendue of the original LED chip wellenough and a substantial amount of light is lost so that it does not hitthe micro display, and in addition to that the remaining light may havetoo wide opening angle. Too wide opening angle causes loss of lightbecause part of the light propagates out of the optics area, and alsothe losses in LCD, LCoS, polarization beam splitters, filters etc.increase with the increasing opening angle. The contrast ratio alsodecreases when opening angle increases in many projector configurations.

FIGS. 2A and 2B illustrate the affect of the carefully designeddistribution of the divergence angle of the beam. FIG. 2A shows atypical situation with the existing light collimation structures. Themost efficient projector configurations demand some optical components210 between the source unit 202 and the microdisplay 204 and/or alsobetween the micro display 204 and the focusing objective 206. As it canbe seen in FIG. 2A the beam divergence causes substantial losses whichcan not be avoided if the size of the micro display and/or the size ofthe objective and other optical components are not increased.

FIG. 2B presents the situation with the source unit 208 of theinvention. The etendue of the source chip is preserved substantiallybetter. In addition to that, the divergence angle distribution isdesigned so that the loss is minimized at the whole length of theprojector. The transmission losses in the micro display 204,polarization components, X-cubes, dichroic mirrors, lenses, diffractiveelements etc. decrease when the opening angle of the beam decreases. Onemajor benefit of the innovation is that the opening angle of the beam isminimized that leads to smaller losses in the other optical componentsthan with the conventional solutions.

The source unit of the present invention is close to an ideal etendueand total flux preserving component that deforms the intensity and angledistribution of the input beam so as to meet the requirements for themicro display, but at the same time, so as to minimize the total beamdivergence. The main design principle is that the special requirementsfor individual components are met as well as possible, but the etenduepreserved as far as possible. The optimization parameters include thearea, light intensity distribution, angle, and beam divergence at everyposition of the projector. The principal figure of merit is the ratio“flux out of projector divided by the electrical power consumed by theoptical sources”. There are also secondary criteria, such asillumination uniformity and contrast. The preceding equations allowplenty of optimization possibilities in design.

The source unit of the invention comprises one or more source chipswhich are integrated with a beam forming component. One embodiment ofthe source unit comprises one source chip integrated with a beam formingcomponent. Another embodiment of the source unit comprises severalsource chips, each providing light with the same wavelength band, andeach integrated with a beam forming component of its own. The beamforming components are designed so that the beams together form thedesired beam. These source subunits can be integrated into a single unitso that they comprise a single unit, which may be beneficial in certaindevice assemblies. The combined beam forming components can further havea common beam forming component which improves the performance of thewhole unit.

Still another embodiment of the source unit comprises more than onenarrow band sources, some or each of which are working with a differentnarrow wavelength band. Typically the source unit comprises red, greenand blue LEDs, for example. Each source is integrated with a beamforming component. The beam forming components are designed so thatbeams together form the desired beam. These source subunits can beintegrated into a single unit so that they comprise a single unit. Forexample, the source unit may comprise six LED chips so that there is twoLEDs with red, green and blue colors. The combined beam formingcomponents can further have a common beam forming component whichimproves the performance of the whole unit.

In the source unit of the present invention, the source chip isintegrated into a beam forming component. This means that the sourcechip is surrounded with a substantially transparent material. Dependingon the structure of the source chip, it can consist of parts withdifferent refractive indexes. The refractive index of the transparentmaterial can be chosen so that it reduces the reflections from theborder of the chip and the transparent material into its minimum, and soraises the external efficiency of the source chip. Typically therefractive index of the transparent material is matched as close to therefractive indexes of the source chip as possible with the availablematerials and manufacturing processes. In one embodiment of theinvention a diffraction grating is manufactured onto the surface of thesource chip between the source chip and the transparent material inorder to further raise the external efficiency of the source chip.

In one embodiment of the invention the source chip is mounted on areflective metal surface. The metal layer reflects the downwards emittedlight upwards. The other function of the metal layer is to conduct anyheat away. A metal mirror can also be deposited onto the surface of someparts of the source chip in order to decrease the etendue. For example,the upper surface of a surface mounted LED chip could be metallized inorder to reduce the etendue.

The beam forming component comprises of a transparent material, whichsurrounds the source chip or source chips and whose refractive index ismatched accordingly. The beam forming component comprises at least onediffractive element. Optionally the beam forming component can compriserefractive and reflective components too. Typically all components areintegrated together so that the beam forming component comprises asingle unit. It is also possible that some elements of the beam formingcomponent are not integrated into the other elements. The refractive anddiffractive elements may have antireflection coatings on them, too. Thebeam forming element may be partially or fully filled with asubstantially transparent material.

FIG. 3A shows one embodiment of the source unit comprising a source chip302 integrated with a a beam forming component. The beam formingcomponent 320 comprises of a transparent material 306 the refractiveindex of which is near that of the source chip 302. The upper surface ofthe transparent material has a certain shape and texture. The beamforming component comprises at least one diffractive element 308.Optionally it may also comprise a refractive component 310. A sourcechip 302 is mounted on a reflecting metal layer 304, which reflects thedownwards emitted light.

FIG. 3B presents a structure otherwise similar to that of FIG. 3A,except that the transparent material 306 has a shape of rectangularblock with straight sides. This demonstrates the situation without thediffractive and refractive components. The object would be to obtainefficient light beam, which propagates upwards from the source chip. InFIG. 3B only the light 312 which is emitted almost upwards from the chipcan avoid total internal reflection, because of the refractive indexdifference between the block material and air. In addition to that, theout coupled beam is diverged substantially in the border of thetransparent material and air. After all, the external efficiency of thesource is very low and the out coming beam diverges noticeably.

The diffractive element 308 has a diffractive surface pattern. Thesurface comprises local diffractive areas which have been optimized sothat most of the light coming from the source chip to that area isdiffracted into desired direction. For example by using suitable binaryor blazed profile, it is possible to obtain, for example, 95% of thelight diffracted to the desired direction. The directionality is thebetter the smaller the source chip is in comparison to the distance fromthe surface point to the source chip. The out coming beam direction canbe designed to be made predetermined by suitable design and by using avarious diffractive patterns which vary over the surface. The period,the shape and pattern, the modulation depth and the duty cycle can beset to best fulfil the desired function. Typically just above the sourcechip the surface is only refractive, whereas elsewhere the surface isdiffractive.

In another embodiment of the beam forming component, which is shown inFIG. 3C, the source chip 302 is sunk in a reflector cup. FIG. 3C alsoshows that the transparent material can also be nearly rectangular inits shape, the surface of which comprise diffractive areas andoptionally also refractive areas.

FIG. 3D presents embodiment where the beam forming component consist ofa reflective component too. The light emitted from the source chip 302to the side is reflected from the mirror 314 to the desired direction.The mirror can be planar, parabolic, elliptical, spherical or some otherin its shape. There may optionally be diffractive components on thesurface of the mirror. The mirror 314 and the metal layer 304 cancomprise a single unit. The mirror 314 can also be integrated into thetransparent material 306.

FIG. 3E shows another embodiment of the beam forming component, wherethe mirror is constructed by using the total internal reflection in theborder of the transparent material 316. The reflected light is directedthrough the surface 318 to the desired direction. The surface 318 cancontain diffractive and refractive elements.

FIG. 3F shows still another embodiment of the beam forming component.The sidewalls of the transparent material 306 have diffractive and/orrefractive surface patterns 308, too.

One embodiment of the source unit comprises of three source chips withred, green and blue colors. All three chips are integrated with the samebeam forming component. A beam forming component comprising at least onediffractive element is typically optimized for one color. In thisembodiment the optimization is done for all three colors at the sametime. In some of the following optical configurations this solutionwould provide extremely compact device.

The said embodiments of the beam forming component were very simpleexamples. The structure is not limited only to the presentedembodiments, but it can be very complicated depending on theapplication. The structure of the beam forming component must be verycarefully designed according to the said design principles taking intoaccount the whole optical system of the device. It is desired that thebeam forming component can be easily mass-produced by well known massproduction methods. This adds some constraints and limitations which hasto be taken into consideration already in the design phase.

The needed geometrical shape for the refractive and reflective elementscan be calculated by using conventional optical design methods. Opticaldesign softwares like Zemax (Zemax Development Corporation, San Diego,Calif., USA) or ray-tracing softwares like TracePro (Lambda ResearchInc., Cincinnati, Ohio, USA) may be used in simulations. In principle,the needed geometrical parameters of the diffractive component can besolved analytically in a very simple case. However, the analyticalsolution is usually too complex in comparison to much faster and simplernumerical modeling. Numerical modeling of diffraction gratings ispossible for example by using GSOLVER (Grating Solver DevelopmentCompany, Allen, Tex., USA) software. GSOLVER utilizes a full3-dimensional vector code using hybrid Rigorous Coupled Wave Analysisand Modal analysis for solving diffraction efficiencies of arbitrarygrating structures for plane wave illumination. In addition to thecommercial software, a skilled professional can use conventionalprogramming tools for building more sophisticated modelling tools of hisown.

Micro Display:

A micro display can comprise an LCD (liquid crystal device), DMD(digital micro mirror device), or LCoS (liquid crystal on silicon) basedspatial modulators or other available micro displays. LCD or LCoS canutilize only one polarization state at time. In LCD micro displays,20%–40% loss happens due to the gaps between the effective pixels. Abetter solution is to use a micro-lens array (MLA) with the LCD, i.e.MLA-LCD. The micro-lens array before (and possibly also after) the microdisplay guides the light through the effective pixel area only. LCD orMLA-LCD must be used in the transmissive micro display configurationsbecause DMD and LCoS micro displays are reflective. On the other hand,LCD can be used also in reflective configurations because a mirror canbe positioned behind the LCD screen. The micro display may produce livevideo images or static images with no movement.

Focusing Unit:

Focusing unit images the image area of the micro display or severalmicro displays to the target. The target (not shown in the Figures) canbe any surface on which the user wants the image to be projected, forexample, a wall, a sheet of paper, a book, a screen or the like. Thefocusing unit can comprise for example a single lens, a Fresnel lens, asingle mirror, a diffractive optical element, a hybridrefractive-diffractive element, or a combination of the said components.Preferably the focusing unit comprises of a set of lenses. Thecomponents in the focusing unit may have an antireflection coating toreduce reflection losses.

In the virtual display applications, the image area of the micro displayor micro displays is imaged to to a virtual plane which can be in thefront of or behind it. For example in the virtual display glasses, theprojector projects the image into the semireflective glasses so that theimage is not formed on the surface of the glasses but for example on thevirtual plane 2 meters ahead.

Monochromatic Projector Architectures:

FIG. 4A shows an embodiment of the data projector, which uses only onewavelength band. The data projector comprises the abovementioned sourceunit 402 with a single color, a transmissive micro display 404 and afocusing unit 406. The source unit 402 provides light to the microdisplay. The image of the micro display 404 is projected onto the targetthrough the focusing unit 406.

FIG. 4B shows another embodiment of the data projector, which uses onlyone source unit 402. The data projector comprises a source unit 402, anoptional mirror 408 which directs the beam to the DMD micro display 410which reflects the light through the focusing unit 406 to the target.

FIG. 4C shows still another embodiment of the data projector, which usesonly one source unit 402. The data projector comprises a source unit402, a polarizing beam splitter 414, a LCoS micro display 412 and afocusing unit 406. The other polarization state of the beam is reflectedby the polarizing beam splitter to the micro display. The LCoS microdisplay modulates the polarization of the beam so that the light fromthe wanted pixels passes through the polarization beam splitter againand gets projected to the target. There may optionally be a quarter-waveplate 416 between the polarization beam splitter 414 and the microdisplay 412, which increases the achievable contrast ratio. The contrastratio can also be improved by using an optional pre-polarizer 418between the source unit 402 and the polarizing beam splitter 414.

When LCD, MLA-LCD or LCoS-based micro displays are used, the otherpolarization direction, i.e. 50% of the light is lost. This loss isavoided in an embodiment which is presented in FIG. 5. The beam from asource unit 502 is directed to the polarization beam splitter 504, wherethe beam is splitted into two directions both consisting of only onelinearly polarized light. The both beams illuminate separate LCD microdisplays 506, 508. The beams are combined again by using mirrors 510,512 and the second polarization beam splitter 514. The images of themicro displays are projected onto the target by the focusing unit 516.This way the both polarization states are utilized.

FIG. 6 presents another modification of the previous embodiment in whichtwo LCoS micro displays are used instead of transmissive LCD panels. Thebeam from the source unit 602 is splitted into two beams in thepolarization beam splitter 604.

The both beams are reflected from the separate micro displays 606, 608and according to the polarization modulation of the micro display, thelight from the wanted pixels of the micro display is directed to thefocusing unit 610. The optional quarter-wave plates 612, 614 can be usedto improve the contrast ratio.

The embodiments presented in FIG. 5 and FIG. 6 are especially beneficialin that point that the projector acts both in 2D and 3D mode. Theembodiments include two separate micro displays, which can be drivenwith the same image (2D-mode) or with two separate images which form astereo-pair (3D-mode).

Still another two embodiments which preserve the both polarizationstates of the light are presented in FIG. 7 and FIG. 8. In FIG. 7 thelight beam from the source unit 702 is divided into two linearlypolarized beams by the polarization beam splitter 704. The reflectedbeam illuminates half of the LCD micro display 706. The transmitted beamfrom the polarization beam splitter is reflected from the mirror 708 andpropagates through the half-wave plate 710 to the other half of themicro display 706. The micro display is then imaged to the target byusing the focusing unit 712. The half-wave plate 710 is used to turn thepolarization state of the beam 90 degrees so that the beam can pass themicro display 706. The half-wave plate 710 is not needed when the microdisplay 706 comprises of two separate LCD panels, whose polarizationdirections are perpendicular to each other.

In principle, FIG. 8 presents a similar embodiment for reflective LCoSmicro display. The light beam from the source unit 802 is divided intotwo linearly polarized beams by the first polarization beam splitter804. As in FIG. 4C, the polarization of the reflected beam from thefirst beam splitter is modulated by the first half of the LCoS microdisplay 806. The light from the wanted pixels of the micro displaypasses through the beam splitter 804 again and propagates to thefocusing unit 808. The transmitted beam from the first polarization beamsplitter 804 is reflected by the second polarization beam splitter 810to the second half of the micro display 806. Similarly this light ismodulated by the micro display and projected into the target. This ispossible because the polarization directions of the polarization beamsplitters 804 and 810 are perpendicular to each other. The embodimentsof FIG. 7 and FIG. 8 are very compact but still preserve the bothpolarization states of the light.

Color Projector Architectures:

Typically three wavelength bands are used in projection, namely red,green and blue. If several wavelength bands are used, the differentwavelength bands are modulated with different micro displays, or withdifferent areas of one micro display, or with the same micro display butwith different time moments in series, because micro displays areinherently monochromatic.

One embodiment of the color projector includes three single-colorprojectors which are aligned together so that they form a color image atthe target together. This embodiment would consist of three focusingunits, which is expensive. A better solution is to use threesingle-color projectors without the focusing units, combine the beamstogether and direct the combined beam to a common focusing unit. Thecombination of the three beams can be done by using X-cube or dichroicmirrors, for example.

FIG. 9A illustrates embodiment wherein three single-color projectors(Red 902R, Green 902G and Blue 902B), based on the embodiment in FIG.4A, are combined by using a X-cube to form a color projector. The lightfrom the source unit 902R illuminates the LCD micro display 904. TheX-cube 906 combines the three beams to one beam which is then projectedby the focusing unit 908 into the target.

FIG. 9B presents almost a similar embodiment, wherein the two dichroicmirrors 910, 912 are used instead of the X-cube to beam combination.

The color projectors in FIGS. 9A and 9B were constructed by combiningthe beams from three single color projectors which was presented in FIG.4A. Similarly, the color projector can be built by combining threesingle color projectors of other above mentioned forms. For example, thesingle color projectors presented in FIGS. 4B, 4C, 5, 6, 7 and 8 can beused to build a color projector similar way.

In the abovementioned color projector architectures several differentmicro displays (or different areas of the same micro display) wasneeded. FIG. 10A presents an embodiment where only one micro display isused. The three different light source units 1002B, 1002G and 1002Rilluminate the micro display 1004 with red, green and blue beams. Thereis a beam steering element 1006 front of the micro display which directsthe beams with different colors through different pixels. Optionally,there is another beam steering element 1008 after the micro display inorder to reduce the divergence of the beam. The beam steering elementscan be for example a micro-lens arrays, a lenticular sheets or amicro-prism arrays. The beam steering elements can be integrated withthe micro display. The image from the micro display is projected to thetarget by the focusing unit 1010. The amount of the pixels on the targetwill be one third of the amount of the pixels of the micro display.

FIG. 10B presents another embodiment of the previous solution. Thestructure is similar otherwise but the three separate source units1002B, 1002G and 1002R are replaced by one source unit 1012 whichcomprises of red, green and blue source chips and which is designed tohave a good efficiency for all three colors. One embodiment of theinvention combines the configurations presented in FIG. 10A or in FIG.10B with the polarization preserving ideas of FIGS. 5, 6, 7 or 8.

As mentioned above, it is possible to use only one micro display in acolor projector by illuminating it in rapid series one color at a time.This solution simplifies the device configuration substantially. Becausea convenient screen would need a refreshing frequency of at least 60 Hz,all colors should be shown during 17 ms time period. When using threecolors, this means an illumination time of 5.7 ms per color. The microdisplay should have a response time short enough. DMD-based microdisplays have a response time of under a millisecond, which is enough.The response time of LCoS micro displays is few milliseconds, forexample 2.2 ms, which is also enough. The commercial LCD response timeis typically 16 ms, but faster ones have already been developed. In afew years the response time of LCD is supposed to go down to 7 ms rangewhich would be enough. It is known that when LEDs are driven in arapidly pulsed mode, the total averaged optical output power can be thesame as when they are driven in DC mode with the same averagedelectrical power. Thus pulsing the LEDs affects negatively neither thepower efficiency of the system nor the absolute optical power of thesystem.

The optical configurations of the color projector in which all thecolors use the same microdisplay serially are the same that thesingle-color projector configurations presented in FIGS. 4A, 4B, 4C, 5,6, 7 and 8, in which the single-color source units are replaced by athree-color source unit. One embodiment of a three-color source unit isa source unit of the innovation comprising of red, green and blue sourcechips and which is designed to have a good efficiency for all threecolors. Another embodiment of a three-color source unit comprises ofthree single-color source units whose beams are combined by using forexample a X-cube or two dichroic mirrors. Some of the preferredembodiments according to these said combinations of single-colorprojector and three-color source are illustrated in following figures.

FIG. 11 presents one embodiment of the color projector where serialillumination is used. The red, green and blue beams from the threesource units 1102B, 1102G and 1102R are combined in a X-cube 1104. As inthe FIG. 5, the beam is directed to the polarization beam splitter 1106,where the beam is splitted into two directions both consisting of onlyone linearly polarized light. The both beams illuminate separate LCDmicro displays 1108, 1110. The beams are combined again by using mirrors1112, 1114 and the second polarization beam splitter 1116. The images ofthe micro displays are projected onto the target by the focusing unit1118.

FIG. 12 presents another embodiment of the color projector where serialillumination is used. The red, green and blue beams from the threesource units 1202B, 1202G and 1202R are combined in a X-cube 1204. As inthe FIG. 6, the beam is splitted into two beams in the polarization beamsplitter 1206. The both beams are reflected from the separate LCoS microdisplays 1208, 1210 and according to the polarization modulation of themicro display, the light from the wanted pixels of the micro display isdirected to the focusing unit 1212. The embodiments in FIG. 11 and FIG.12 provide 2D/3D-switcable color projector with a compact deviceconfiguration.

FIG. 13 presents still another embodiment of the color projector whereserial illumination is used. The red, green and blue beams from thethree source units 1302B, 1302G and 1302R are combined in a X-cube 1304.As in the FIG. 7, the beam is divided into two linearly polarized beamsby the polarization beam splitter 1306. The reflected beam illuminatesthe first LCD micro display 1308. The transmitted beam from thepolarization beam splitter is reflected from the mirror 1310 to thesecond LCD micro display 1312. The micro displays 1308, 1312 are thenimaged to the target by using the focusing unit 1314.

FIG. 14A presents still another embodiment of the color projector whereserial illumination is used. The red, green and blue beams from thethree source units 1402B, 1402G and 1402R are combined in a X-cube 1404.As in the FIG. 8, the beam is divided into two linearly polarized beamsby the first polarization beam splitter 1406. The polarization of thereflected beam from the first beam splitter 1406 is modulated by thefirst half of the LCoS micro display 1408. The light from the wantedpixels of the micro display passes through the beam splitter 1406 againand propagates to the focusing unit 1410. The transmitted beam from thefirst polarization beam splitter 1406 is reflected by the secondpolarization beam splitter 1412 to the second half of the micro display1408. Similarly this light is modulated by the micro display andprojected into the target. This is possible because the polarizationdirections of the polarization beam splitters 1406 and 1412 areperpendicular to each other.

The embodiments of the invention as they are presented in FIGS. 13 and14A are suitable only for 2D projection. However by replacing thefocusing units 1314 and 1410 by a focusing unit with a beam splitter theembodiments are suitable for both 2D and 3D projection. This isillustrated in FIGS. 14B and 14C. FIG. 14B presents the embodiment ofFIG. 14A modified to have both 2D and 3D projection capability. Thetotal internal reflection prisms 1414, 1416 have been added after thefocusing unit 1410. The prisms direct the both beams with perpendicularpolarization states to the same position on the target so that whenviewed through a polarization glasses they produce a 3D-image together.

FIG. 14C presents another embodiment of the beam splitter with thefocusing unit. The focusing unit 1410 is replaced by two focusing units1418, 1420 which are positioned after the beam splitter. By thissolution the edges of the projected screen are possibly sharper than bythe embodiment presented in FIG. 14B. The beam splitter can also beimplemented by using mirrors instead of prisms.

FIG. 15 shows an embodiment of the color projector with the serialillumination, similar to that of presented in FIG. 14 but wherein theX-cube and the three separate source units are replaced by one sourceunit 1502 which comprises of red, green and blue source chips and whichis designed to have a good efficiency for all three colors.

FIG. 16, instead, shows an embodiment of the color projector with theserial illumination, similar to that of presented in FIG. 14 but whereinthe X-cube is replaced by two dichroic mirrors 1602, 1604.

FIG. 17 presents an embodiment of the color projector where serialillumination is used. The red, green and blue beams from the threesource units 1702B, 1702G and 1702R are combined in a X-cube 1704. As inthe FIG. 4B, an optional mirror 1706 directs the beam to the DMD microdisplay 1708 which reflects the light through the focusing unit 1710 tothe target.

Although in the abovementioned color projector embodiments the usedcolors were red, green and blue, we are not restricted to these colors,but the colors can be any three colors in the visible range. Anotherchoice of colors could be cyan, yellow and magneta, for example. Also,in some applications two colors are enough. In some cases it might befruitful to use even four or more colors. The combination of such a manycolors is possible by using dichroic mirrors for example. It is clearthat modifications to the abovementioned optical configurations can bedone in the scope of the invention. The abovementioned configurationswere included as examples of possible embodiments. Depending on theapplication, by adding optical components to the abovementioned basiclayouts, it is possible to affect to the quality of the projection. Forexample mirrors, diffractive elements, lenses, optical filters, quarter-and half-wave plates can be added in many positions without changing thebasic idea of the invention. In addition to that, optical components canmany times be replaced with other components which have similarfunction, for example mirrors can be replaced by total internalreflection prisms. Many components can be integrated together so thatthey comprise a single unit. In some applications it is preferably tohave all components integrated together for example by using transparentmaterial between the optical components. Abovementioned micro displayscan be replaced by other spatial modulators which have suitablefunctionality.

The data projector of the invention can be used in various projectionset-ups. The most straightforward set-up is direct projection, in whichthe projector projects the image onto a surface, which can be a silverscreen, a wall, or a paper for example. The projected image is viewedand illuminated on the same side of the surface. In certain applicationsit is beneficial to use direct projection to a semitransparent surfacewhich can be semi-reflecting or diffusing surface. Another form ofprojection is back projection, in which the projector illuminates asemitransparent diffuse surface, which is then viewed on the oppositeside of the surface than illuminated. Still another form of projectionis virtual screen projection, in which the image of the micro display ormicro displays is projected into a virtual plane.

3D-Projection:

In some of the abovementioned embodiments the beam was divided into twoperpendicular polarization states which were then modulated separately.This enables to project both polarizations with different images bycontrolling micro displays separately. Thus it is possible to projectboth 2D and 3D images with the same projector. When viewing 3D images,polarization glasses are required. In the abovementioned directprojection, the polarization must be preserved in the reflection fromthe projection surface. This can be achieved by using for examplemetallized screens. In the back projection set-up the polarizationtypically preserves without special arrangements or screen materials.FIG. 18 presents a back projection system as an example of 3D projectionset-up. The data projector 1802 projects two images with differentpolarization states to the back projection screen 1804 which is thenviewed through the polarization glasses 1806.

Electrical circuits can be implemented by hardware on a circuit boardwhich comprises separate electronic components, by VLSI components (VeryLarge Scale Integrated Circuit), by FPGA components (Field-ProgrammableGate Arrays) or preferably e.g. by ASIC circuit technology (ApplicationSpecific Integrated Circuit). Automatic data processing can be carriedout in a PC computer or preferably by software run in a processor.

The projection method and data projector according to the invention areparticularly suitable for the following uses:

-   -   as a television replacement    -   as a computer monitor replacement    -   as a video projector    -   as a slide presenter/slide projector    -   as a virtual display projector

The solution of the invention can also be used as an accessory to orintegrated into:

-   -   mobile phone    -   DVD—and other media players    -   video camcorder    -   digital camera    -   Personal Digital Assistant    -   Laptop PC    -   handheld and desktop gaming devices    -   video conferencing device    -   head mounted display    -   military display    -   multimedia devices at home, hotels, restaurants, cars,        airplanes, ships and other vehicles, offices, public buildings        such as hospitals, libraries, etc; and other locations    -   any of the abovementioned uses together with 3D imaging software        & hardware such as ray tracing, CAD, 3D modeling, 3D capable        graphics cards, 3D movies & games for providing 3D viewing of        desired objects    -   any other device in which low power consumption, small size and        low price are important aspects.

All in all, the present invention leads to a significantly smallerprojector configuration, using less power, yielding lower costs andproviding higher durability than the existing devices.

Even though the invention is described above with reference to examplesaccording to the accompanying drawings, it is clear that the inventionis not restricted thereto but it can be modified in several ways withinthe scope of the appended claims.

1. A data projector comprising: at least one micro display; at least onelight source chip; and an optically transmissive beam forming componentarranged to enclose substantially a hemisphere about the light sourcechip, where the beam forming component is disposed to directsubstantially all light, from the light source chip into the hemisphere,toward the microdisplay with substantially uniform illumination, wheresaid beam forming component comprises at least one of a diffractive or arefractive surface pattern.
 2. The data projector of claim 1, whereinthe data projector comprises at least one green LED, at least one blueLED and at least one red LED as light sources.
 3. The data projector ofclaim 1, wherein the data projector comprises an LCD, LCoS, DMD, MLALCD, MLA LCoS display or the like as the micro display.
 4. The dataprojector of claim 1, wherein the data projector further comprises anoptical unit between the beam forming component and the micro displayfor directing the optical radiation more efficiently, the optical unitbeing a lens, a mirror, a fresnel lens, a diffractive element, a microlens array, x-cube or other optical component or a series of these orany combination thereof.
 5. The data projector of claim 1, wherein thedata projector further comprises an optical unit between the microdisplay and the focusing unit for directing the optical radiation moreefficiently, the optical unit being a lens, a mirror, a fresnel lens, adiffractive element, a micro lens array, x-cube or other opticalcomponent or a series of these or any combination thereof.
 6. The dataprojector of claim 1, wherein the data projector further comprises:means for dividing the beam of light from each light source into twobeams with different polarizations, the micro display being divided intoseparate parts or using two separate micro displays to which each beamof the two beams of each light source is directed.
 7. The data projectorof claim 6, wherein the data projector further comprises means forcombining the two beams of light of each light source after the microdisplay.
 8. The data projector of claim 1, wherein the refractive indexof the transparent material in each beam forming component is equal orclose to equal to the refractive indexes of the corresponding sourcechip.
 9. The data projector of claim 1, wherein each beam formingcomponent is integrated with a corresponding light source chip.
 10. Thedata projector of claim 1, wherein the image is a video image.
 11. Thedata projector of claim 1, wherein the data projector is a part of aportable electronic device.
 12. The data projector of claim 6, whereinthe two different polarizations are projected with separate images whichform a stereo pair and viewed with polarization glasses to enable 3Deffect.
 13. The data projector of claim 1, wherein the target is avirtual plane.
 14. The data projector of claim 1 in the following uses:television, computer monitor, video projector, slide presenter/slideprojector, virtual display projector.
 15. The data projector of claim 1as an accessory to or integrated into: a mobile phone, a DVD- or othermedia player, a video camcorder, a digital camera, a Personal DigitalAssistant, a Laptop PC, a handheld or desktop gaming device, a videoconferencing device, a head mounted display, a multimedia device athome, hotels, restaurants, cars, airplanes, ships and other vehicles;multimedia devices at offices, public buildings and other locations;military displays.
 16. The data projector of claim 1, wherein the beamforming component further directs substantially all light, from thelight source chip into the hemisphere, toward the microdisplay with adesired projection shape and uniform illumination.
 17. The dataprojector of claim 1, further comprising a focusing optical unit forprojecting the image of the micro display on a target.
 18. The dataprojector of claim 1, wherein the said at least one of a diffractive ora refractive surface pattern is disposed on an optically transmissivesurface of the beam forming component, further wherein at least one of adiffractive or a refractive surface pattern is disposed on an opticallyreflective surface of the beam forming component.
 19. The data projectorof claim 1, wherein the beam forming component comprises a transparentmaterial adjacent to the light source chip that has an index ofrefraction matched to that of the light source chip.
 20. The dataprojector of claim 19, wherein the matched indices of refraction arewithin about 0.4 of one another.
 21. A data projector comprising: atleast one micro display; and at least one source unit comprising atleast one light source chip, said source unit further comprising atleast one beam forming component disposed in a three dimensionalconfiguration to substantially enclose a hemisphere about the lightsource chip, wherein an optically transmissive surface and an opticallyreflective surface of the beam forming component each comprise at leastone of a diffractive and a refractive surface pattern.
 22. The dataprojector of claim 21, wherein the data projector comprises at least onegreen LED, at least one blue LED and at least one red LED as lightsources.
 23. The data projector of claim 21, wherein the data projectorcomprises an LCD, LCoS, DMD, MLA LCD, MLA LCoS display or the like asthe micro display.
 24. The data projector of claim 21, wherein the dataprojector further comprises an optical unit between the beam formingcomponent and the micro display for directing the optical radiation moreefficiently, the optical unit being a lens, a mirror, a fresnel lens, adiffractive element, a micro lens array, x-cube or other opticalcomponent or a series of these or any combination thereof.
 25. The dataprojector of claim 21, wherein the data projector further comprises anoptical unit between the micro display and the focusing unit fordirecting the optical radiation more efficiently, the optical unit beinga lens, a mirror, a fresnel lens, a diffractive element, a micro lensarray, x-cube or other optical component or a series of these or anycombination thereof.
 26. The data projector of claim 21, wherein thedata projector further comprises: means for dividing the beam of lightfrom each light source into two beams with different polarizations, themicro display being divided into separate parts or using two separatemicro displays to which each beam of the two beams of each light sourceis directed.
 27. The data projector of claim 26, wherein the dataprojector further comprises means for combining the two beams of lightof each light source after the micro display.
 28. The data projector ofclaim 21, wherein the refractive index of the transparent material ineach beam forming component is equal or close to equal to the refractiveindexes of the corresponding source chip.
 29. The data projector ofclaim 21, wherein each beam forming component is integrated with acorresponding light source chip.
 30. The data projector of claim 21,wherein the image is a video image.
 31. The data projector of claim 21,wherein the data projector is a part of a portable electronic device.32. The data projector of claim 26, wherein the two differentpolarizations are projected with separate images which form a stereopair and viewed with polarization glasses to enable 3D effect.
 33. Thedata projector of claim 21, wherein the target is a virtual plane. 34.The data projector of claim 21 in the following uses: television,computer monitor, video projector, slide presenter/slide projector,virtual display projector.
 35. The data projector of claim 21 as anaccessory to or integrated into: a mobile phone, a DVD- or other mediaplayer, a video camcorder, a digital camera, a Personal DigitalAssistant, a Laptop PC, a handheld or desktop gaming device, a videoconferencing device, a head mounted display, a multimedia device athome, hotels, restaurants, cars, airplanes, ships and other vehicles;multimedia devices at offices, public buildings and other locations;military displays.
 36. The data projector of claim 21, where said atleast one source unit is operable to preserve etendue and minimizephoton loss.
 37. The data projector of claim 21, wherein the beamforming component comprises a light emitting diode.
 38. The dataprojector of claim 21, wherein the beam forming component is disposed toprovide a desired projection shape and a substantially uniformillumination onto the micro display.
 39. The data projector of claim 21,further comprising a focusing optical unit for projecting the image ofthe micro display on a target.
 40. The data projector of claim 21,wherein the beam forming component comprises a transparent materialadjacent to the source unit that has an index of refraction matched tothat of the source unit.
 41. The data projector of claim 38, wherein thematched indices of refraction are within about 0.4 of one another.
 42. Amethod of data projection comprising: operating at least one lightsource chip of at least one source unit for illuminating at least onemicro display, while preserving etendue, and minimizing photon loss;where operating the at least one light source chip comprises beamforming the illumination to provide a desired projection shape and asubstantially uniform illumination using a plurality of surfacesdisposed in a three dimensional configuration that substantiallyencloses a hemisphere about the light source chip, where said at leastone optically reflective surface of the plurality of surfaces comprisesat least one of a diffractive and a refractive surface pattern, focusinga desired image resulting from illumination of the micro display; andprojecting the focused image onto a target.
 43. A method as in claim 42,wherein the at least one light source chip comprises a LED (LightEmitting Diode) source.
 44. A method as in claim 42, wherein an opticaloutput of the at least one light source chip has a bandwidth of aboutone nanometer to about 150 nanometers.
 45. A method as in claim 42,wherein an optical output of the at least one light source chip has abandwidth of about 10 nanometers to about 50 nanometers.
 46. A method asin claim 42, wherein the at least one light source chip is mounted on areflective surface.
 47. A method as in claim 42, wherein the at leastone light source chip is mounted on a reflective metal surface toconduct heat away.
 48. A method as in claim 42, wherein the beam formingcomponent comprises a reflective component.
 49. A method as in claim 42,wherein the at least one source unit comprises at least three lightsource chips outputting red, green and blue light, the at least threelight source chips being integrated with the beam forming component, thebeam forming component comprising at least one diffractive elementoptimized for red, green and blue simultaneously.
 50. A method as inclaim 42, wherein the micro display comprises at least one of an LCD(liquid crystal device), a DMD (digital micro mirror device), a LCoS(liquid crystal on silicon) based spatial modulator and a micro-lensarray (MLA) with a LCD.
 51. A method as in claim 42, wherein focusingcomprises using at least one of a single lens, a fresnel lens, a singlemirror, a diffractive optical element, and a hybridrefractive-diffractive element.
 52. A beam forming component disposed ina three dimensional configuration to substantially enclose a hemisphereabout a light source having a light source chip, where at least oneoptically reflective surface of the beam forming component, within thehemisphere, comprises micro-optical structures, the beam formingcomponent further comprising a transparent material adjacent to thelight source chip that has an index of refraction matched to that of thelight source chip.
 53. The beam forming component of claim 52, furthercomprising a micro display disposed adjacent to an opticallytransmissive surface of the beam forming component.
 54. The beam formingcomponent of claim 53, wherein the beam forming component is configuredto provide substantially uniform illumination to the micro display. 55.The beam forming component of claim 52, wherein an opticallytransmissive surface of the beam forming component, within thehemisphere, comprises micro optical structures.
 56. The beam formingcomponent of claim 52, in combination with a reflective substrate thattogether substantially envelope the light source.
 57. The beam formingcomponent of claim 52, wherein the matched indices of refraction arewithin about 0.4 of one another.
 58. The beam forming component of claim52 in combination with a micro display, said beam forming componentdisposed to provide a substantially uniform illumination onto a microdisplay.
 59. The beam forming component of claim 58 further disposed toprovide a desired projection shape onto the micro display.
 60. A dataprojector comprising: a light source having a light source chip; a microdisplay; and a beam forming component comprising a transparent materialadjacent to the light source that has an index of refraction matched tothat of the light source chip, said beam forming component definingmicro optical structures at least along a surface that is notperpendicular to a line between the light source and the micro-display.61. The data projector of claim 60, wherein the beam forming componentis disposed to substantially enclose a hemisphere about the lightsource.
 62. The data projector of claim 60, wherein the said surface isa portion of an arcuate surface.
 63. The data projector of claim 60,wherein the beam forming component further comprises at least oneoptically reflective surface that defines micro optical structures. 64.The data projector of claim 60, wherein the beam forming component andthe micro optical structures are disposed to provide substantiallyuniform illumination at the micro display.
 65. The data projector ofclaim 60, wherein the light source comprises a reflective substrate thatsubstantially envelops the light source with the beam forming component.66. The data projector of claim 60, wherein the matched indices ofrefraction are within about 0.4 of one another.
 67. A data projectorcomprising: a light source; a micro display; and a beam formingcomponent comprising a plurality of planar optically transmissivesurfaces having micro optical structures on at least three of saidplanar surfaces that are not perpendicular to a line between the lightsource and the micro display.